"Base filesystem does not exist" during install from usb


Hi to all doudou fans first and foremost. I am on my second install to a Dell E4300 laptop, the first was to a Dell D630 which went reasonably ok. When I run sudo live-installer and work through the info screens the gui launches and the install seems to start. At the bottom of the screen it says “calculating file indexes”. If i minimise the install screen to see the terminal it appears all is not well. It is erroring at the partitioning of the disk and says

" you must specify a file system type failed to mount /dev/sda1"

it then says the same for sda2 and sda3.
This is followed by

Base filesystem does not exist! Critical error (exiting).

Any help would be greatly appreciated. Thanks.

closed #2

opened #3